|Funerals for those killed in Yeonpyeong were held on Monday as Seoul launched the navy drills [Reuters]
South Korea has started a nationwide live-fire naval exercise, despite warnings from Pyongyang against staging what it describes as provocative drills in disputed waters off the divided peninsula.
"The drills have started," a spokesman for the South's military said on Monday.
The exercises are scheduled to take place at 29 sites in seas near the disputed Northern Limit Line (NLL).
North Korea has said that the exercises, expected to last for a week, showed the South was "hell-bent" on setting off a war.
Tensions between the two neighbours have risen following Pyongyang's artillery strike that left four people dead on Yeonpyeong, a South Korean border island, late last month.
Al Jazeera's Marga Ortigas, reporting from Seoul, said the timing of the naval drills seems "rather inappropriate considering the way things have been here over the last two weeks".
She said it is part of the South Korean government's efforts to "take more more forceful steps when it comes to dealing with North Korean provocation".
"The previous defence minister was let go for failing to protect the country.
"But now South Korea has a new defence minister who is determined to show he is a man of his word. There are many expectations resting on his shoulders," she said.
North Korea disputes the NLL, a sea border established by the United Nations, without Pyongyang's consent, at the end of the 1950-53 Korean War.
The locations of the drills include the Daecheong Island, one of five major islands near the Yellow Sea border, where the Cheonan, a 1,200-tonne South Korean naval vessel, was hit by a suspected North Korean missile in March, resulting in the deaths of 46 sailors on board. An international investigation blamed North Korea for the sinking.
But military officials have previously said the drills would not take place near Yeonpyeong.
The live-fire exercise comes as Japan and the US stage one of their biggest-ever joint military exercises, which began on Friday, just days after the United States and South Korea conducted smaller exercises aimed at deterring an aggressive North Korea.
The foreign ministers of South Korea and Japan will meet Hillary Clinton, the US secretary of state, in Washington on Monday to discuss North Korea. They are expected to produce a statement condemning Pyongyang's actions.
China, the North's only major ally and the chair of stalled international nuclear talks with Pyongyang, is not invited.
However, the three countries are expected to discuss Beijing's proposal for emergency regional talks on the Korean crisis.
South Korea has sharply increased its rhetoric over the past week, prompted by public opinion polls critical of the conservative government's perceived weak response to the Yeonpyeong attack.
Kim Kwan-jin, the South's new defence minister, has vowed to hit back hard against the North if provoked again, saying Seoul will respond with bombs and air power next time.